Automatic feed for percussive drills.



G. C.' HANSEN.

AUTOMATIC FEED Pon PERGUSSIVB DBILLs.

APPLICATION FILED JULY 19, 1912.

N @LN WCS@ A TTHNEY c. G. HANSEN. AUTOMATIC FEED FOB PERGUSSIVE DRILLS.

Patented Sept. 30,- 1913.

2 SHEETS-SHEET 2 APPLICATION FILED JULY 19, 1912.

.w N E Tl t Q E wmlfssfs.-

UNITED sTATEs PATENT OFFICE. N

CHARLES c. HANSEN, E EASTON, PENNSYLVANIA, AssIGNoR To INGEBsoLL-EANDCOMPANY, or NEwYonx, N. Y., A coEPoEATIoN or NEW JERSEY.

y AUTOMATIC FEED FOR PERCUSSIVE IDRILLS.

Specication'of Letters Patent.

. vApplication iled July 19, 1812. Serial No. 710,373.

Patented Sept. 30, 1913.

'ToaZZ whom, it may concern: Be it known that I, CHARLES C. HANSEN,

a citizen of the United States, residing 1n Easton, in the county ofNorthampton and State of Pennsylvania, have invented certaln new anduseful Improvementsin Automatic Feeds for Percussive Drills, of whichthe following is a specification.

This invent-ion relates to percussive drills and more particularly toa-rack and pawl construction for automatically feeding such drillstoward their work. Feeding mechanism of this type is not new and it isold in the art to provide a stationary rack secured to a support onwhich a hammerdrill 1s slidably mounted and to provide thedrill withpawls which engage the stationary lrack. Y

The object of the present invention is to provide a rack and pawlfeeding means of new and improved construction which allows the rack andpawl or pawls to be quickly and simply disengaged from each other whenit is desired to return the drill to the beginning of its feed and alsoto pro/ vide a means whereby the drill can be held lin its rearmostposition when it is desired to move the drill, change steels, or doanything else requiring the drill to be ixedly held.

lVith this object in view I have devised a feeding means the practicalembodiment of which is shown in the accompanying drawings in which-Figure 1 shows the plan of the complete drill Fig. 2 shows the sectionthrough Fig. 1 on the line II-II, showing the feeding rack in elevationFig. 3 shows an c nlarged section of the rear part of the drill showingthe. paw-1 mechanism and the rack 40 turned to hold the drill in itsrearmost position and Fig. 4 is a section through the line IV-IV of Fig.3 showing the rear end of the ydrill in elevation.

The tool as shown consists of a hammer ,45 drill 1 of ordinaryconstruction, slidably mounted by means of flanges 2 secured theretowhich slide in grooves in thesupporting shell 3. The lower part of thebackhead 4 of the drill is extended rearwardlyand its 50 lower face isprovided with three transversely bored sockets in which are mounted vthree pawls 6, 7 and 8, two of which, 6 and 7, extend rearwardly fromtheir sockets and the other 8 extends forwardly therefrom. 55 Thesepawls are secured in position by plates plungers 12 mounted in theholding the 9 and 10 which are fastened to the backhead by bolt-s 11 andcontact with the side faces of the pawls, which extend completely acrossthe width of the baekhead. Spring pressed backhead ipress the pawls intooperative position. Coperating with thesepawls and rotatably mounted 1nbearings 13, 14 and 15 on the drill shell is a rack 16, which consistsof a round bar a I portion of the circumference of which is providedwith a row of teeth 17 extending the greater part of the length of thebar'and 'having forwardly facing surfaces for engaging the pawls 6 and7. The pawls 6 and are so spaced that they do not both engage the teeth17 at the same time. On the opposite side of the bar near the rear endythereof are a few teeth 18 having backwardly facing surfaces forengaging the pawl 8. The rest of the surface of the bar is entirelysmooth.

The bearing 15' is provided with a stop mechanism consisting of a springpressed ball 19 which is adapted to engage opposite recesses 20 in thesurfaces of the rack bar to hold it in any desired position. The handle21is secured to the rear end of the rack bar providing a means to rotateit.

In operation when it is desired to start the drill in its work the rackbar 16 is turned to the position shown in Fig. 2 with the teeth 17uppermost and in position to be engaged by the pawls 6 and 7. The drilll willv feed forwardly when the air 'is turned on by the impact of thepiston on the front head and the pawls 6 and 7 vwill engage teeth 17 andprevent any backward movement of the drill. `When the drill has reachedthe limit of its forward movement which will be when the pawl 6 engagesthe last of the teeth 17, the rack 16 can be rotated by means of thehandle 21 so thatthe pawls 6 and 7 engage the smooth surface of the rackbar thus enabling the drill to be slid backwardly to its rearmostposition without any hindrance from the pawls, this rotation beingpossible when the drill is at any posit-ion on the shell. If it isdesired to hold the drill in its Arearmost position the rack bar 16 canbe turned so that the teeth 18 are uppermost as in Fig. 3 when the pawl8 will come into operation engaging one of the teeth 18 and rillsecurely in position on the support-ing shell. y

Although the rack bar is here 'shown secured to and rotatable on thesupporting means and thefp'awls attached to the drill the positions ofthe rack and awl could be reversed without invention an the rack barsecured to the drill `while the pawls could be fastened on thesupporting means, and it is to be understood that the present showingdiscloses but one modification of my invention and other modificationssuch as that mentioned above are included in the spirit and scope ofthev invention asexpressed in the claims.y

WhatI I`claim is: Q

1. In combination with a `hammerdrill slidably mountedon a supporting'means, a rack and pawl mechanism for -automatically feeding said drillforward, said rack comprising a rotatably mounted bar having a portionof its surface provided with an eX- tended row of feeding teeth,'asmooth portion, and a portion near 'its rear end provided withV one ormore holdin teeth said z pawl mechanism comprising bac ardiy extendingcpawls for engaging said feeding teeth an 4a forwardly extending pawlfor engaging said holding teeth. l

2. n combination a support, drill slidably mounted thereon, a rack barrotatably mounted on said support, said rack bar-.having one Aportion ofits surface iprovided with feeding'teeth, a separate portlon withholding teeth disposed oppositely-fto said feedin teeth, two sets ofpawls secured to said dr' for engaging said teeth, and means to rotatesaid rack bar from a osition of engagement with one set of paw toengagement with 'the other set. 1 CHARLES C. HANSEN.

Witnesses:

JOHN F. Mocx, WM. C. MORRIS.

